A police forensics investigator approaches a crime scene where one man was killed in Woolwich, southeast London May 22, 2013. British Prime Minister David Cameron has called a meeting of his government's emergency Cobra security committee after the killing of a man in south London, his office said on Wednesday.

LONDON — British Prime Minister David Cameron called an emergency security meeting on Wednesday after a man was killed near an army barracks in London, and two men were shot and wounded by police.

Media reports said the dead man was a British soldier who was hacked to death by unidentified assailants. Some reports suggested his attackers tried to behead him while shouting "God is greatest" in Arabic.

"This is a sickening and barbaric attack," Home Secretary Theresa May said in a statement.

Britain's government convenes meetings of its emergency security committee only to deal with incidents that have implications for national security. A security source told Reuters on condition of anonymity that it was too soon to say whether the incident was terror related.

Security was tightened in the area immediately after the attack but details were sketchy. Helicopters hovered above the residential area and nearby roads were sealed off by the police.

"(That) this can happen in the centre of a busy town, it's really really shocking and traumatising for everybody, all local residents," a witness who gave her name as Tenisan told Reuters in a nearby street.

London was last hit by a serious attack in July 2005 when four young men set off suicide bombs on the underground and bus network, killing 52 people and injuring hundreds. Four others failed to repeat a similar attack two weeks later.

A second attack, aimed at a packed nightclub in central London, in 2007 failed when police found two car bombs packed with petrol, gas and nails in London's theatre district on a busy weekend night.

Photographs posted online showed at least two people on the ground who appeared to be injured, but no further details were immediately available.

A teacher at a local school told the BBC earlier he saw a body on the road and afterwards heard gunshots.

"A number of weapons were reportedly being used in the attack, and this included reports of a firearm," London police said in a statement.